Distance detecting sensor and close range detecting method

ABSTRACT

The present invention discloses a distance detecting sensor, comprising: a casing, focusing lenses, a circuit board mounted with several electronic elements, and an emitting device emitting infrared light and a receiving device receiving and sensing a reflected infrared light. Wherein, the casing comprises a main body and two round openings on the top surface of the main body. The lenses comprise an emitting lens and a receiving lens arranged at the openings of the casing. The circuit board is mounted in the main body of the casing; the emitting device is an infrared emitting diode (LED), emitting infrared light toward the emitting lens. The receiving device is a distance detecting sensor module, which senses the reflected light focused by the receiving lens. The distance detecting sensor further comprises an emitting light guide unit arranged between the emitting lens and the emitting device, and the emitting light guide unit comprises small round holes at the emitting tube core of the emitting device. The present invention has higher detection accuracy and improves the overall detection performance of the sensor.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a Continuation of U.S. application Ser. No.12/612292, filed Nov. 4, 2009, which claims priority to China P.R.Priority Application 200810202228.3, filed Nov. 5, 2008. Both U.S. Ser.No. 12/612,292 and China P.R. Priority Application 200810202228.3 areincorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a distance detecting sensor applicablein the technical field of sanitary automation (e.g., automatic sensingfaucets, automatic flushing urinals, etc.) and a close range detectingmethod of the distance detecting sensor.

BACKGROUND ART

Infrared sensors have been widely used in sanitary wares, such asautomatic faucets, automatic flushing urinals, toilet flushing devices,hot water spraying toilet seats, hand driers, and toilets provided withhot air fan.

Most conventional infrared sensors adopt an active infrared detectionmanner, in which an infrared emitter emits an infrared light at aspecific wavelength, the infrared light is reflected from human body andthe signal strength of the reflected signal is judged after beingreceived by an infrared receiver, thereby to achieve automatic sensingand judgment. However, it is difficult to achieve the automatic sensingand judgment for substances with low infrared reflectivity (e.g., blackclothing, hair, etc.). After the infrared light from the infraredemitter is reflected by such substances, only a small amount of infraredlight is received by the infrared receiver. Since the intensity ofreflected signal is not high enough, the sensor is unable to judgewhether there exists an object, and therefore the sensing fails.

In order to solve the sensing failure problem of conventional infraredsensing sanitary ware, a distance detecting sensor is introduced intothe field of sanitary automation. As shown in FIG. 1, a positiondetecting sensor, or called as position sensitive detector (PSD) is aphotoelectric device that is sensitive to the position of incidentlight. That is to say, when the incident light irradiates at differentpositions on the photosensitive surface of the device, differentelectric signals can be outputted. The PSD achieves automatic detectionand judgment by utilizing the triangular measurement principle withwhich distance can be measured accurately. As shown in FIG. 1, the lightemitted from the light emitting source S.sub.1 is focused by a lens L1and then projected onto the surface of an object O1 to be detected. Thereflected light is focused by a lens L2 onto a one dimensional PSD(i.e., a receiving unit P1), and forms a light spot. Suppose the centerdistance between lens L1 and L2 is b, the distance from lens L2 to thesurface of the PSD (i.e., focal length of lens L2) is f, and thedistance from the light spot focused on the surface of the PSD to thecenter of lens L2 is x, it can be obtained based on the nature ofsimilar triangles PAB and BCD that the distance DIS to be measured willbe DIS=bf/x. Therefore, the distance of the object to be detected can bemeasured as long as the position coordinate x of the light spot on thePSD is obtained.

If it is detected that the distance of the object O1 falls within apreset range, the distance detecting sensor will control the operationstates, including for example water output, flushing and etc, of thesanitary ware. Since the distance detecting sensor achieve the object ofautomatic detection by judging the distance between the object and thedistance detecting sensor, it can effectively overcome the drawback ofsensing failure of conventional infrared sensors.

However, there are some requirements for detection distance when such adistance detecting sensor is used. If the distance from the object to bedetected to the distance detecting sensor is too close, the infraredlight emitted from the light emitting source of the distance detectingsensor can't be focused onto the surface of the PSD, and therefore thedetection will fail. For example, when such a distance detecting sensoris mounted on a faucet, if the hands of the user are too close to thedistance detecting sensor, sensing failures happen easily.

Therefore, it is necessary to invent a distance detecting sensor and amethod that can effectively overcome the drawback in the prior art.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a distance detectingsensor that can detect more reliably.

The object of the present invention is attained with the followingtechnical solution:

a distance detecting sensor mounted in sanitary ware, comprising: aninfrared light emitting source, an infrared light receiving unit, and anemitting lens and an receiving lens, arranged in front of the lightemitting source and the receiving unit respectively to focus infraredlight. The receiving unit is a photo-electric device that is sensitiveto the position of infrared light. At least a close range light emittingsource is arranged near the light emitting source. The light emittingsource and the close range light emitting source are light emittingdiodes (LEDs).

Furthermore, the emission power of the infrared light emitting source ishigher than that of the close range light emitting source.

Furthermore, the emission frequency of the infrared light emittingsource and the close range light emitting source is lower when there isno object to be detected than when there is an object to be detected.

Another object of the present invention is to provide a close rangedetection method, which makes the distance detecting sensor operatesmore reliably.

The above object of the present invention can be attained with thefollowing technical solution:

A close range detection method of a distance detecting sensor,comprising the following steps:

Step 1: activating a light emitting source to emit an infrared light,and proceeding to step 2;

Step 2: judging whether a receiving unit receives a reflected infraredlight signal; if the receiving unit receives a reflected infrared lightsignal, going to step 5; otherwise proceeding to step 3;

Step 3: activating a close range light emitting source to emit aninfrared light, and proceeding to step 4;

Step 4: judging whether the receiving unit receives a reflected infraredlight signal; if the receiving unit receives a reflected infrared lightsignal, proceeding to step 5; otherwise returning to step 1;

step 5: calculating the distance value of an object to be detected basedon the received infrared light reflected from the object;

Step 6: judging whether the distance value of the object is within apreset range; if the distance is within the preset range, proceeding tostep 7; otherwise returning to step 1;

Step 7: controlling the action of the sanitary ware.

Furthermore, the emission power of the light emitting source is higherthan that of the close range light emitting source.

Furthermore, the emission frequency of the light emitting source and theclose range light emitting source is lower when there is no object to bedetected than when there is an object to be detected.

Alternatively, the objects of the present invention can be attained withthe following technical solution:

A close range detection method of a distance detecting sensor,comprising the following steps:

Step 1: activating a light emitting source and a close range lightemitting source synchronously to emit an infrared light respectively,and proceeding to step 2;

Step 2: judging whether a receiving unit receives an reflected infraredlight signal; if the receiving unit receives an infrared light signal,proceeding to step 3; otherwise returning to step 1;

Step 3: calculating the distance value of an object to be detected basedon the received infrared light reflected from the object, and proceedingto step 4;

Step 4: judging whether the distance value of the object is within apreset range; if the distance is within the preset range, proceeding tostep 5; otherwise returning to step 1;

Step 5: controlling the action of the sanitary ware.

Furthermore, the emission power of the light emitting source is higherthan that of the close range light emitting source.

Furthermore, the emission frequency of the light emitting source and theclose range light emitting source is lower when there is no object to bedetected than when there is an object to be detected.

Alternatively, the object of the present invention can be attained withthe following technical solution:

A close range detection method of a distance detecting sensor,comprising the following steps:

Step 1: activating a close range light emitting source to emit aninfrared light, and proceeding to step 2;

Step 2: judging whether a receiving unit receives an infrared lightsignal reflected from an object to be detected; if the receiving unitreceives a reflected infrared light signal, proceeding to step 3;otherwise returning to step 1;

Step 3: calculating the distance value of the object to be detectedbased on the received infrared light reflected from the object, andproceeding to step 4;

Step 4: judging whether the distance value of the object is within apreset close range; if the distance is within the preset close range,going to step 8; otherwise proceeding to step 5;

Step 5: activating a light emitting source to emit an infrared light,and proceeding to step 6;

Step 6: judging whether the receiving unit receives an infrared lightsignal reflected from the object to be detected; if the receiving unitreceives an infrared light signal reflected from the object, proceedingto step 7; otherwise returning to step 1;

step 7: judging whether the distance value of the object is within anormal range; if the distance value is within the preset normal range,proceeding to step 8; otherwise returning to step 1;

Step 8: controlling the action of the sanitary ware.

Furthermore, the emission power of the light emitting source is higherthan that of the close range light emitting source.

Furthermore, the emission frequency of the light emitting source and theclose range light emitting source is lower when there is no object to bedetected than when there is an object to be detected.

Compared with the prior art, the close range detection method of thedistance detecting sensor provided in the present invention caneffectively prevent incorrect operation resulted from mirrorinterference, make the distance detecting sensor operates more reliably,and thereby improve the overall detection performance of the distancedetecting sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an operational principal diagram of a distance detectingsensor of the prior art.

FIG. 2 is a structural schematic diagram of a distance detecting sensorin accordance with the present invention.

FIG. 3 is a flow chart of a close range detection method of a distancedetecting sensor in accordance with an embodiment of the presentinvention.

FIG. 4 is a flow chart of a close range detection method of a distancedetecting sensor in accordance with another embodiment of the presentinvention.

FIG. 5 is a flow chart of a close range detection method of a distancedetecting sensor in accordance with still another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various embodiments of the present invention will be detailed withreference to the accompanying drawings, in which identical structures orfunctionalities are designated with the same reference numbers. It isnoted that the accompanying drawings are provided only for convenienceof explanations of the embodiments, and are not superfluous descriptionor any limitation to the present invention. In addition, theaccompanying drawings may not be drawn to scale.

As shown in FIG. 2, the distance detecting sensor 100 in accordance withthe present invention includes a light emitting source S1, a receivingunit P1, an emitting lens L1 and a receiving lens L2 arranged in frontof the light emitting source S1 and the receiving unit P1 respectively.The light emitting source Si is an infrared light emitting source,generally an LED. The receiving unit P1 is a photo-electric device, i.e.a PSD module that is sensitive to the position of incident infraredlight on its surface. Specially, a close range light emitting source S2is further arranged beside the light emitting source S1 of the distancedetecting sensor 100. The close range light emitting source S2 is alsoan infrared light emitting source, generally an LED.

As shown in FIG. 1, if an object 01 to be detected is in a normaldetection area, the infrared light emitted from the light emittingsource S1 is focused by the emitting lens L1 and then irradiated ontothe object 01. The infrared light is reflected from the object O1, andthe reflected infrared light can be focused by the receiving lens L2 andthen irradiated onto the receiving unit P1. Furthermore, the distancefrom the object O1 to be detected to the distance detecting sensor 100of the present invention is calculated on the basis of the PSD triangleprinciple. If the calculated distance is within the preset range, thedistance detecting sensor 100 will control valve-open, valve-close andetc. of the sanitary ware through its main controller and furthercontrol actions of the sanitary ware such as water output and flushing.However, if the object O1 to be detected is too close to the distancedetecting sensor 100, the case is different, specifically described asfollows:

The distance detecting sensor 100 of the present invention is mounted onsanitary ware, such as a faucet or urinal, etc. The object to bedetected (e.g., hands or body of the user) is often too close to thedistance detecting sensor 100 of the present invention, especially inthe situation where the distance detecting sensor 100 is mounted on afaucet, in which the hands of the user tend to stretch out towards theposition of the detector (i.e., the distance detecting sensor 100). Insuch a case, the emitted infrared light, after irradiated onto theobject to be detected, can not be normally reflected onto or can not bereflected onto the receiving unit and therefore can not be sensed. Thus,the distance detecting sensor 100 can't detect the object 01. Thiseventually results in non-operation of the corresponding sanitary waresuch as faucet and urinal.

Further, as shown in FIG. 2, the infrared light emitted from the lightemitting source S1 reaches the object O1 to be detected and is reflectedfrom the object O1. Since the object O1 is too close to the distancedetecting sensor 100, the infrared light MB reflected from the object O1can't be focused by the receiving lens L2 onto the receiving unit 2.Therefore, the distance detecting sensor 100 of the present inventioncan't detect existence of the object O1, with the result that thesanitary wares such as faucet and urinal do not operate.

In view of the above, a close range light emitting source S2 is arrangedbeside the light emitting source S1 of the distance detecting sensor100, to specially detect whether any object O1 exists within a rangethat is less than the normal detection range (i.e., close range). Whenthe light emitting source S1 can't detect the object 01, the close rangelight emitting source S2 is activated to emit an infrared light. Becausethe infrared light emission angle of the close range light emittingsource S2 is designed specially for close range detection, if the objectO1 exists within the range that is less than the normal detection range,the light emitted from the close range light emitting source S2 willirradiate on the object O1 and will be reflected, and the reflectedinfrared light NA can be focused by the receiving lens L2 onto thereceiving unit P1. Thereby, the distance detecting sensor 100 of thepresent invention can detect existence of the object O1 and calculatethe distance value, on the basis of triangular principle. If thedistance value is within a preset range, the distance detecting sensor100 of the present invention can control the sanitary wares (faucet,urinal, etc.) by means of its main controller to act (e.g., open thevalve, and etc.). The preset distance range described above needs to beconfigured in advance according to actual application environments,specifically, whenever it is judged that an object to be detected iswithin the preset distance range, it is believed that some user wants touse or is using a corresponding sanitary ware; and then, the sanitaryware controls the on-off valve before, during and after the useaccording to actual situations, thereby achieving automatic control ofsanitary ware.

As shown in FIG. 3, a close range detection method of the distancedetecting sensor 100 in accordance with the present invention mainlycomprises the following steps:

Step 1: activating the light emitting source Si to emit an infraredlight, and proceeding to step 2;

Step 2: judging whether the receiving unit P1 (i.e., the PSD module)receives a reflected infrared light signal; if the receiving unit P1receives a reflected infrared light signal, going to step 5; otherwiseproceeding to step 3;

Step 3: activating the close range light emitting source S2 to emit aninfrared light, and proceeding to step 4;

Step 4: judging whether the receiving unit P1 receives a reflectedinfrared light signal; if the receiving unit P1 receives a reflectedinfrared light signal, going to step 5; otherwise returning to step 1;

Step 5: calculating the distance value of an object O1 to be detectedbased on the received infrared light reflected from the object O1, andproceeding to step 6;

Step 6: judging whether the distance value of the object O1 is withinthe preset range; if the distance value of the object O1 is within thepreset range, proceeding to step 7; otherwise returning to step 1;

Step 7: determining that some user wants to use or is using the sanitaryware, and controlling the corresponding sanitary ware by means of a maincontroller to perform operations such as opening or closing valve).

In accordance with the above preferred embodiment, if it is detectedthat an object is within the normal distance range, it is not necessaryto activate the close range light emitting source, so that the powerconsumption can be saved more effectively. Of course, in accordance withanother embodiment of the present invention, the close range lightdetection method of distance detecting sensor 100 in the presentinvention can be that: the light emitting source S1 and the close rangelight emitting source S2 emit an infrared light synchronously; then, itis judged whether the receiving unit P1 receives an infrared light, andwhether the position of the object O1 to be detected is within a presetrange; and finally, the operations (opening/closing the valve, and etc.)of the sanitary ware (faucet, urinal and etc.) is controlled accordingto the result of judgment. The specific steps of the method are asfollows:

Step 1: activating a light emitting source S1 and a close range lightemitting source S2 synchronously, and proceeding to step 2;

Step 2: judging whether a receiving unit P1 receives a reflectedinfrared light signal; if the receiving unit P1 receives a reflectedinfrared light signal, proceeding to step 3; otherwise returning to step1;

Step 3: calculating the distance value of an object O1 to be detectedbased on the received infrared light reflected from the object O1, andproceeding to step 4;

Step 4: judging whether the distance value of the object O1 is withinthe preset range; if the distance value of the object O1 is within thepreset range, proceeding to step 5; otherwise returning to step 1;wherein, the preset range includes a preset normal range and a presetclose range.

Step 5: controlling the corresponding sanitary ware to performoperations such as opening or closing valve).

Furthermore, the emission frequency of infrared light when an object isdetected is different from when no object is detected. The emissionfrequency is lower when no object is detected than when an object isdetected. In a preferred embodiment of the present invention, theemission frequency of infrared light is once per 0.3 s when no object O1is detected, and is once per 0.15 s when an object O1 is detected. Suchan arrangement is favorable for saving of power consumption.

Furthermore, in actual applications, since the close range lightemitting source S2 is used for close range detection, the power foractivating the close range light emitting source S2 to emit infraredlight is higher than the power for activating the light emitting sourceSi to emit infrared light. In a preferred embodiment of the presentinvention, the current for activating the light emitting source Si toemit infrared light is about 70 mA, while the current for activating theclose range light emitting source S2 to emit infrared light is about 20mA.

Since the power for activating the close range light emitting source S2to emit infrared light is lower, the close range light emitting sourceS2 is normally open in another embodiment of the present invention. Whenan object is detected within the close range detection area, thesanitary ware will be controlled to profound actions such as openingvalve.

The close range light emitting source S2 can also faintly detect whetheran object O1 enters into the normal detection area. As a consequence,after the close range light emitting source S2 emits an infrared lightand detects that an object O1 enters into the normal detection area, thelight emitting source S1 is activated to emit an infrared light, todetect the object accurately. When an object is detected accurately inthe normal detection area, it can be judged that the distance value ofthe object is within the preset range, and the corresponding sanitaryware is controlled to perform actions such as opening valve. This ishelpful for saving of power consumption. The specific steps of themethod are as follows:

Step 1: activating the close range light emitting source S2 to emit aninfrared light, and proceeding to step 2;

Step 2: judging whether the receiving unit P1 receives an infrared lightsignal reflected from object O1 to be detected; if the receiving unit P1receives a reflected infrared light signal, proceeding to step 3;otherwise returning to step 1;

Step 3: calculating the distance value of the object O1 based on thereceived infrared light signal reflected from the object O1, andproceeding to step 4;

Step 4: judging whether the distance value of the object O1 is within apreset close range; if the distance value is within the preset closerange, going to step 8; otherwise proceeding to step 5;

Step 5: activating the light emitting source S1 to emitting an infraredlight, and proceeding to step 6;

Step 6: judging whether the receiving unit P1 receives an infrared lightsignal reflected from the object O1; if the receiving unit P1 receives areflected infrared light signal, proceeding to step 7; otherwisereturning to step 1;

Step 7: judging whether the distance value of the object O1 is within apreset normal range; if the distance value is within the preset normalrange, proceeding to step 8; otherwise returning to step 1;

Step 8: controlling the corresponding sanitary ware to perform actions(e.g. opening/closing valve, and etc.).

In addition, in the embodiments of the present invention, two or moreclose range light emitting sources S2 can be arranged to attain betterclose range detection effect.

Although some embodiments of the present invention have been disclosedabove, the present invention is not limited to them. Those skilled inthe prior art can make various modifications or variations to theembodiments described above without departing from the scope of thepresent invention.

What is claimed is:
 1. A distance detecting sensor mounted in sanitaryware, comprising: an infrared light emitting source, an infrared lightreceiving unit, and an emitting lens and an receiving lens in front ofthe light emitting source and the receiving unit respectively designedto focus infrared light; wherein, the light emitting source and a closerange light emitting source are LEDs, and the receiving unit is aphotoelectric device that is sensitive to the position of infraredlight; wherein, at least a close range light emitting source is arrangednear the light emitting source.
 2. The distance detecting sensoraccording to claim 1, wherein, the emission power of the light emittingsource is higher than that of the close range light emitting source. 3.The distance detecting sensor according to claim 1, wherein, theemission frequency of the light emitting source and the close rangelight emitting source is lower when there is no object to be detectedthan when there is an object to be detected.
 4. A close range detectionmethod of the distance detecting sensor according to claim 1, comprisingthe following steps: step 1: activating the light emitting source toemit an infrared light, and proceeding to step 2; step 2: judgingwhether the receiving unit receives a reflected infrared light signal;if the receiving unit receives a reflected infrared light signal, goingto step 5; otherwise proceeding to step 3; step 3: activating the closerange light emitting source to emit an infrared light, and proceeding tostep 4; step 4: judging whether the receiving unit receives a reflectedinfrared light signal; if the receiving unit receives a reflectedinfrared light signal, proceeding to step 5; otherwise returning to step1; step 5: calculating the distance value of an object to be detectedbased on the received infrared light reflected from the object; step 6:judging whether the distance value of the object is within a presetrange; if the distance is within the preset range, proceeding to step 7;otherwise returning to step 1; step 7: controlling the correspondingsanitary ware to perform actions.
 5. The distance detecting sensoraccording to claim 4, wherein, the emission power of the light emittingsource is higher than that of the close range light emitting source. 6.The distance detecting sensor according to claim 4, wherein, theemission frequency of the light emitting source and the close rangelight emitting source is lower when there is no object to be detectedthan when there is an object to be detected.
 7. A close range detectionmethod of the distance detecting sensor according to claim 1, comprisingthe following steps: step 1: activating the light emitting source andthe close range light emitting source synchronously to emit an infraredlight, and proceeding to step 2; step 2: judging whether the receivingunit receives a reflected infrared light signal; if the receiving unitreceives a reflected infrared light signal, proceeding to step 3;otherwise returning to step 1; step 3: calculating the distance value ofan object to be detected based on the reflected infrared light receivedfrom the object, and proceeding to step 4; step 4: judging whether thedistance value of the object is within a preset range; if the distanceis within the preset range, proceeding to step 5; otherwise returning tostep 1; step 5: controlling the corresponding sanitary ware to performactions.
 8. The close range detection method of the distance detectingsensor according to claim 7, wherein, the emission power of the lightemitting source is higher than that of the close range light emittingsource.
 9. The close range detection method of the distance detectingsensor according to claim 7, wherein, the emission frequency of thelight emitting source and the close range light emitting source operateis lower when there is no object to be detected than when there is anobject to be detected.
 10. A close range detection method of thedistance detecting sensor according to claim 1, comprising the followingsteps: step 1: activating the close range light emitting source to emitan infrared light, and proceeding to step 2; step 2: judging whether thereceiving unit receives an infrared light signal reflected from anobject to be detected; if the receiving unit receives a reflectedinfrared light signal, proceeding to step 3; otherwise returning to step1; step 3: calculating the distance value of the object to be detectedbased on the received infrared light reflected from the object, andproceeding to step 4; step 4: judging whether the distance value of theobject is within a preset close range; if the distance value is withinthe preset close range, going to step 8; otherwise proceeding to step 5;step 5: activating the light emitting source to emit an infrared light,and proceeding to step 6; step 6: judging whether the receiving unitreceives an infrared light signal reflected from the object; if thereceiving unit receives a reflected infrared light signal, proceeding tostep 7; otherwise returning to step 1; step 7: judging whether thedistance value of the object to be detected is within a preset normalrange; if the distance value is within the preset normal range,proceeding to step 8; otherwise returning to step 1; step 8: controllingthe corresponding sanitary ware to perform actions.
 11. The close rangedetection method of the distance detecting sensor according to claim 10,wherein, the emission power of the light emitting source is higher thanthat of the close range light emitting source.
 12. The close rangedetection method of the distance detecting sensor according to claim 10,wherein, the emission frequency of the light emitting source and theclose range light emitting source is lower when there is no object to bedetected than when there is an object to be detected.